Solder feeder, printer, and printing method

Abstract

Disclosed is a print technology in which a solder pool staying on the surface of a mask is driven by means of a squeegee, and solder is applied onto a substrate onto which the lower surface of a mask is placed. A forward print process where solder is applied by driving a squeegee in a predetermined forward direction relative to a mask, and a backward print process where the solder is applied by driving the squeegee in a returning direction opposite to the forward direction are switched alternately. When the squeegee passes through the solder pool on the downstream side in a moving direction before switching in the course of switching from any one of the forward and backward print processes to the other one of these processes, the amount of solder in the solder pool is measured. Based on the amount of solder thus measured, the necessity of replenishing solder is determined. The solder pool is supplemented with solder, based on the result of the decision on whether solder replenishment is required.

1. A solder feeder in a printer, wherein the solder feeder is adapted to replenish a solder pool with solder, and the printer is adapted to execute alternately a forward print process and a backward print process, said printer comprising:
 only one squeegee supported on a head, 
 a drive source fixed to the head, the drive source is adapted to drive the squeegee so that the squeegee is brought into contact with the solder pool from an upstream side of a forward direction when the forward print process is executed, and to drive the same squeegee so that the same squeegee is brought into contact with the solder pool from a downstream side in a forward direction when the backward print process is executed, 
 wherein, in the forward print process, the squeegee is configured to press the solder pool on a surface of a mask from the upstream side in the forward direction while moving the head relatively along the surface of the mask in the forward direction to apply solder onto a substrate through the opening part of the mask of which lower surface is put on the top of the substrate, and 
 wherein, in the backward print process, the same squeegee is adapted to press the solder pool from the upstream side in a returning direction while moving the head relatively along the surface of the mask to apply solder onto a substrate through the opening part of the mask, 
 the solder feeder comprising: 
 solder feeding means for feeding the solder; 
 solder amount measuring means, attached to the head, for measuring an amount of solder in the solder pool when the squeegee passes through the solder pool on the downstream side in a moving direction before switching in a process where switching is made from any one of the forward print process and backward print process to the other; 
 solder replenishment necessity determination means for determining whether solder replenishment is required, based on the amount of solder measured by the solder amount measuring means; and 
 replenishment control means for controlling the solder feeding means to replenish the solder pool with the solder, based on a result of the determination made by the solder replenishment necessity determination means. 
 
     
     
       2. The solder feeder according to  claim 1 , wherein
 the solder amount measuring means has a plurality of sensors attached to the head, and 
 the solder replenishment necessity determination means determines the necessity of replenishing the solder, based on a result of measurement performed by one of the plurality of sensors that is most remote from the squeegee. 
 
     
     
       3. The solder feeder according to  claim 1 , wherein
 the solder amount measuring means measures a width of the solder pool in a relative displacement direction, and 
 the solder replenishment necessity determination means determines the necessity of replenishing the solder by obtaining the width of the solder pool. 
 
     
     
       4. A printer comprising:
 printing means for executing alternately a forward print process, in which only one squeegee supported on a head presses a solder pool staying on a surface of the mask from the upstream side in a forward direction while moving the head relatively along the surface of the mask in the forward direction to apply solder onto a substrate through the opening part of the mask of which lower surface is put on the top of the substrate, and a backward print process, in which the same squeegee presses the solder pool from the upstream side in a returning direction while moving the head relatively along the surface of the mask to apply solder onto a substrate through the opening part of the mask; 
 a drive source fixed to the head, the drive source is adapted to drive the squeegee so that squeegee is brought into contact with the solder pool from the upstream side of the forward direction when the forward print process is executed, and the drive source is adapted to drive the same squeegee so that the same squeegee is brought into contact with the solder pool from the downstream side in the forward direction when the backward print process is executed; 
 solder feeding means for feeding the solder; 
 solder amount measuring means, attached to the head, for measuring an amount of solder in the solder pool when the squeegee passes through the solder pool on the downstream side in a moving direction before switching in a process where switching is made from any one of the forward print process and backward print process to the other; 
 solder replenishment necessity determination means for determining whether the solder pool needs to be replenished with solder, based on a result of the measurement performed by the solder amount measuring means; and 
 replenishment control means for controlling the solder feeding means to replenish the solder pool with the solder, based on a result of the determination made by the solder replenishment necessity determination means. 
 
     
     
       5. A printing method comprising steps of:
 a forward print process in which a squeegee supported on a head presses a solder pool staying on the surface of the mask from the upstream side in a forward direction while moving the head relatively along the surface of the mask in the forward direction, in order to apply solder onto a substrate through the opening part of the mask of which lower surface is put on the top of the substrate; 
 a backward print process in which the squeegee presses the solder pool from the upstream side in a returning direction while moving the head relatively along the surface of the mask in the returning direction, in order to apply solder onto a substrate through the opening part of the mask; 
 a switching process of switching a position of the squeegee in relation to the solder pool when alternately switching between the forward print process and the backward print process; 
 a solder amount measuring process of measuring an amount of solder in the solder pool when the squeegee passes through the solder pool on the downstream side in a moving direction before switching in a process where switching is made from any one of the forward print process and backward print process to the other; 
 a solder replenishment necessity determination process of determining whether solder replenishment is required, based on a result of the measurement performed in the solder amount measuring process; and 
 a replenishing process of replenishing the solder pool with the solder, based on a result of the determination made in the solder replenishment necessity determination process.